On July 20, 2023, diphtheria was laboratory confirmed in the Kankan Region of Guinea, following reports of suspected cases of diphtheria in the region since July 4. Between July 4 and Aug 27, 117 suspected cases were reported, including seven cases that were laboratory confirmed. 37 deaths have been reported (case fatality rate [CFR] of 31·6%), including all seven confirmed cases; nine deaths occurred in the community, indicating continued risk and transmission at the community level. Cases have been reported across four of the five districts in the Kankan region, with Siguiri district reporting the highest number of cases (100 cases), followed by Kankan (eight cases), Mandiana (seven cases), and Kouroussa (two cases).